A091245 Number of reducible GF(2)[X]-polynomials in range [0,n].

0, 0, 0, 0, 1, 2, 3, 3, 4, 5, 6, 6, 7, 7, 8, 9, 10, 11, 12, 12, 13, 14, 15, 16, 17, 17, 18, 19, 20, 21, 22, 22, 23, 24, 25, 26, 27, 27, 28, 29, 30, 30, 31, 32, 33, 34, 35, 35, 36, 37, 38, 39, 40, 41, 42, 42, 43, 44, 45, 45, 46, 46, 47, 48, 49, 50, 51, 51, 52, 53, 54, 55, 56, 56

Offset: 0

Author

Antti Karttunen, Jan 03 2004

Keywords

• nonn

Comments

Analogous to A065855.

Examples

			In range [0,8] there are the following four reducible polynomials: 4,5,6,8 thus a(8) = 4.
		

Links

• A. Karttunen, Scheme-program for computing this sequence.
• Index entries for sequences operating on GF(2)[X]-polynomials

Crossrefs

Partial sums of A091247. Cf. A091242.

Programs

PARI

first(n)=my(s); concat([0,0], vector(n-1,k, s += !polisirreducible(Pol(binary(k+1))*Mod(1,2)))) \\ Charles R Greathouse IV, Sep 02 2015